Vikings concludes its first season on History tonight at 10 PM and has packed a whole lot of Norse adventure-drama into just a handful of episodes. So far, we’ve followed our hero, Ragnar Lothbrok (Travis Fimmel), as he’s successfully raided England, overthrown Earl Haraldson (Gabriel Byrne), and protected his family from a constant stream of threats and intrigue.

There’s a whole lot of story to resolve in tonight’s season finale, so catch up on the four big things you need to know before you watch below.

Things are weird between Ragnar and Lagertha

Unlike most of the other Viking men – we’re looking at you especially, Rollo! – our Ragnar is a one woman man. And for good reason: his wife, Lagertha, is a powerhouse shieldmaiden that is not to be messed with, as she displayed first-thing when she quickly dispatched two would-be attackers in episode one. She’s also drop-dead gorgeous, of course, and played with fierce regal perfection by Katheryn Winnick.

But the last few episodes, especially last week’s “Sacrifice,” have shown the cracks in their union. Lagertha’s recent miscarriage left both wounded, and Ragnar spent much of clan’s traditional pilgrimage to Uppsalla wondering where the many sons the Seer told him the gods would bless him with would come from if not from his loving wife.

Aslaug, played by model-turned-actress Alyssa Sutherland, is a new character introduced in the finale. Journeying from Kattegat to Gotaland (modern day Sweden) to resolve a land dispute for King Horik, Ragnar’s men stumble across her bathing naked in a stream. She demands an apology from Ragnar, and he flirts Viking-style by making her solve a riddle in order to come meet him and get her apology. The chemistry between the pair is immediate and undeniable, as you can see in the EW exclusive clip below from the episode.

It sucks when your best bro brings you on a cool vaycay and then is all, “Oh, I forgot to tell you we’re totes going to sacrifice you to the gods, BTW.”

(Luckily for Athelstan, he hasn’t given up entirely on his Christian faith and was deemed an unacceptable sacrifice to the gods because of it.)

The relationship between Ragnar and the monk he took as a slave during his first raid in England has always been a curiosity. The pair warmed up to one another pretty quickly, given the circumstances – Ragnar even invited Athelstan to join he and Lagertha in bed – and Athelstan assimilated quickly into the Viking way of life in Kattegat. Each seemed to be learning a lot from the other.

So it was pretty unsettling when it was revealed that he’d been brought to Uppsalla as a sacrifice. Now, Ragnar’s comment that Athelstan’s god saved him once again struck us as a sort-of admission that he expected that very thing to happen. (Was it just us? Let us know in the comments below.) But who knows? Ragnar’s relationship with Athelstan is maybe the show’s most dynamic, so hopefully we’ll get a little closure on this topic in the finale.

Ever-tense Rollo is feeling especially betrayed right now

We can’t decide how we feel about Rollo and we’re not always sure the show knows how it feels about Rollo either. Rollo has a serious complex about being Ragnar’s equal, but in the end he comes through for his brother – except there’s always a catch.

He came to Ragnar’s defense in “Trial,” but then claimed he did it for Lagertha, who he has (had? we haven’t heard much about it since) a thing for. Later, when Ragnar became Earl, he pledged fealty, but then turned around and immediately asked Siggy (Jessalyn Gilsig), widow of the former Earl, if she’d like to be married to another Earl, referring to himself.

So, he was already plotting to take his brother’s spot as the boss when Siggy informed him, in the last episode, that Ragnar and Athelstan were meeting with King Horik without him. And boy was he mad. Rollo is too impulsive and bad-tempered on his own to pose much danger to Ragnar’s rule, but with devious and power-hungry Siggy by his side, he becomes more of a threat.

We already know there’s a lot happening in the season finale – Ragnar and his men travel to Gotaland, there’s Aslaug temptation tea to brew, and a plague takes its toll on the village – so we can’t imagine they will get too deep into the brewing Rollo-Ragnar showdown. But you better believe we’ll be keeping our eyes peeled for hints of what’s to come in season two.

According to Sutherland, who was otherwise tight lipped, fans should expect “some things left hanging” from the finale. “There are cliffhangers,” she promised, “how does that sound?”